update csv_testing
set testing5 = case when testing5 like '%N/A%' then '0' when testing5 IS NULL then '0' else testing5 end,
testing6 = case when testing6 like '%N/A%' then '0' when testing6 IS NULL then '0' else testing6 end,
testing7 = case when testing7 like '%N/A%' then '0' when testing7 IS NULL then '0' else testing7 end
where
(testing5 IS NULL or testing5 like '%N/A%') or
(testing6 IS NULL or testing6 like '%N/A%') or
(testing7 IS NULL or testing7 like '%N/A%')